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GRAS on the MetOp satellites


The Meteorological Operational satellite programme (MetOp) is Europe's first polar-orbiting satellite system dedicated to operational meteorology. The data are used to monitor climate and improve weather forecasting. MetOp is a series of three satellites to be launched sequentially over 14 years and forms the space segment of EUMETSAT's Polar System (EPS). The satellite MetOp-A was launched October 19, 2006 and MetOp-B September 17, 2012. MetOp-C is expected to be launched in 2018.

The instrumentation is designed to augment the accuracy of:

  • temperature and humidity measurements,
  • wind speed and wind direction measurements, especially over the oceans, and
  • profiles of ozone in the atmosphere.

GPS radio occultation with GRAS

The GPS Receiver for Atmospheric Sounding (GRAS) provides more than 600 daily atmospheric profiles measured by GPS radio occultation, which are globally distributed. In addition GRAS provides navigation solutions of the MetOp satellite along its orbit. The atmospheric profiles are assimilated into Numerical Weather Prediction (NWP) models.

GFZ activities

GFZ analyses the GRAS data using the GFZ radio occultation processing system and participated in two international studies to evaluate and improve the data quality of GRAS. GFZ also contributes to the GPS ground network for GRAS for provision of GNSS ground and navigation bit data.

Zus F., Beyerle G., Heise S., Schmidt T., Wickert J., Marquardt C.: Validation of refractivity profiles derived from GRAS raw-sampling data, Atmos. Meas. Tech., 4, 1541-1550, 2011.

ESA MetOp Homepage

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